Motion: The change in position of an object
Reference Point: a place or object used for comparison to determine if something is in motion.
(also called frame of reference)
An object is in motion if it changes position relative to a reference point.

Speed: The distance an object travels in one unit of time.
Average Speed (average velocity): v = d ÷ t
(v = velocity, d = distance, t = time)
Example: an object rolls 2 meters in 4 seconds.
2 ÷ 4 = 0.5 m/s
To solve for missing factor when the other 2 are known: t = d ÷ v or d = v∙t

Velocity: Speed in a given direction
(example: 10 km/hr north)
Graph: a picture of the data used to assist in data analysis

Acceleration: The rate at which velocity changes
{change in speed and/or direction}
Acceleration: a = vf – vi t
(a = acceleration, vf = final velocity, vi = initial velocity, t = time)
Ex: an objects initial velocity is 2 m/s but increases to 4 m/s second after 5 seconds
4 m/s – 2m/s = 2 m/s
5 s 5 s 0.4 m/s 2
Δ (delta) is a symbol that means change in.
To solve for missing factors when the other 2 are known: a = Δv÷t
Δv =a∙t t = a∙ Δv

Force: A push or pull exerted on an object
Newton (N): A unit of measure for force.
1 N = the force required to accelerate 1 kg of mass at 1 m/s 2
Balanced Forces: Equal forces acting on an object in opposite directions (no change in motion)
Unbalanced Forces:
A nonzero net force, which changes an object’s motion.
Net Force: The overall force on an object when all individual forces acting on an object are added together.

The 4 Fundamental Forces:
1.
Gravity: The force that pulls objects toward each other
(more detail in later units)
2. Nuclear Forces
Strong Force: force in the nucleus that causes protons and neutrons to be attracted to each other.
Weak Force (electrical force) is a long range force and causes repulsion of protons far apart.
It is responsible for the decay of isotopes
(more in chemistry).
3.
Electromagnetic force
(more detail in later units)
4. Dark Energy : believed to be the cause of universal expansion
(space science)
4 forces video clip